Lymphatic System, White Blood Cells, B Cells - The Players In The Immune System : Part 2

UltraLongevity: The Seven-Step Program for a Younger, Healthier You
By Mark Liponis, M.D.

(Page 2 of 5)

You may have noticed that your feet swell during a long journey on an airplane or in a car. This is due to lack of movement; your muscles haven't been able to circulate lymph, so because of gravity, it collects at the lowest part of your body-your feet.

You also may be aware of a condition known as edema, which is swelling that results from a collection of lymph. Edema occurs when excess lymph fluid cannot be returned back into circulation.

The bloodstream is extensive, branching out from its main trunk, the aorta, as well as smaller arteries, arterioles, capillaries, veins, and venules, but there is still a large portion of our tissues the capillaries can't reach.

Here is where the lymph comes into play. Nutrients such as glucose (blood sugar) must be helped so they can reach and nourish each and every cell, including those the bloodstream can't reach. That happens via the lymph fluid, which bathes and nourishes all of the body's tissues. And once those nutrients have been used, the fluid must be recycled or your body would swell up like the Michelin tire man.

Along the course of the lymphatic system are way stations known as lymph nodes. These are outposts whose sentries make sure nothing passes through the lymphatic channels that shouldn't. The lymphatic system could provide easy and direct access for a germ or microbe to our heart and bloodstream, so to prevent that from happening, lymphocytes (T cells and B cells) aggregate in lymph nodes, waiting for something bad to pass by. When they spot that something, the node cells attack before it can venture into the heart and bloodstream.

When a problem is stirring in your body, the lymph nodes become enlarged. For example, if you have swollen glands in the neck, your nodes may have found some virus that landed in the back of the throat and is trying to gain access to the lungs or bloodstream. Lymph nodes responding to some infection can become swollen almost anywhere: in the groin, neck, chest, abdomen, and so on.

White Blood Cells

Probably the most important cells of our immune system, as well as the best-known and the most numerous, are the white blood cells. This term distinguishes them from the red blood cells, the disk-like cells responsible for carrying oxygen and carbon dioxide from our lungs throughout the rest of the body.

Most people probably think of white blood cells simply as formless globules floating through our bloodstream, randomly patrolling for microbes. But our white blood cells are very purposeful and deliberate in their surveillance, and there are actually many different types of white blood cells, each with specialized functions. And these white blood cells are found not just in the blood, but throughout our bodies-in each of our organs, from the brain to the liver to the lungs, as well as throughout the lymphatic system.

The first line of immune cells are the lymphocytes. Cyte means "cell," so lymphocytes are the lymph or lymphatic cells. The ones you most need to know about are the B lymphocytes (better known as B cells) and the T lymphocytes (better known as T cells).

B Cells

B cells were so named because they were first studied in the bursa of Fabricius, an organ unique to birds. In humans, B cells actually originate in the bone marrow.

The B cells have two major jobs: they maintain a memory database, and they create complex protein structures that are used as weapons against threats and invaders. These complex structures are called antibodies, about which more is coming.

B cells keep a record of every single interaction your immune system has ever had. This means that within your body, a record of every germ and virus you've ever encountered, every protein you've ever eaten, every piece of pollen you've ever inhaled, has been stored in a memory bank-not in your brain, but in your immune system. Think about it: for each of these interactions, there is a B cell floating around inside your body that has retained a memory of the encounter.

Your immune system's memory is, in some ways, more impressive than your brain's. Most of us can only evoke faint memories from early childhood. Your immune system, however, remembers your first vaccination, which probably occurred in the earliest days of your life. Research now suggests that your immune system even stores memories from when you were still developing in your mother's womb.

Shortly after birth, you were probably immunized with vaccines for diphtheria, tetanus, and pertussis (whooping cough). Although the memory of that immunization may fade somewhat, and a booster may be needed to remind your immune system, some remnant of that memory lasts a lifetime.

These stored memories are critically important for your survival; they are what make you immune to becoming sick more than once from certain illnesses.

For example, after a bout of chicken pox in childhood, you become immune-you usually can't catch chicken pox again as an adult. Likewise, after being immunized with a shot for tetanus, you won't succumb to the bacterial infection that causes tetanus. Your B cells now have the memory stored away and prevent you from coming down with the disease.

A memory of exposure to prior threats is crucial because it allows your immune system to respond more quickly and effectively to serious threats if you are re-exposed. Without such a memory, and a rapid response, exposure to ailments such as tetanus or diphtheria could be fatal.

It's also important for your immune system to remember prior contacts and exposures even if they're not potentially lethal, as it makes your immune system less likely to cause an overwhelming reaction when encountering nonlethal microbes. If, for example, your immune system overreacted every time you ate a particular food, or breathed in a particular pollen, you would forever exist in a state of immune hyperactivity and unnecessary battle.

© 2007 by Mark Liponis, MD

About the Author

Mark Liponis, MD, is the medical director of the Canyon Ranch Spa in all its locations. He is the coauthor of New York Times bestseller UltraPrevention, which won the 2003 Books for a Better Life Award in the health category.